The architecture of these mobile telecommunications networks has hitherto been standardized via a standardization group known by the name 3GPP. Such is in particular the case for the so-called “2G”, “3G” and “4G” mobile networks, whose various architectures are defined in technical specifications established by such a body.
Up to the “4G” generation of mobile network currently being rolled out, the various network architectures relied on very specific equipment dedicated to certain precise functionalities, be it at the level of the access network or of the network core, in particular as regards the transmission of packets from or to a mobile terminal.
The lack of flexibility and of upgradability inherent in this type of conventional architecture has led to envisaging the adoption of more flexible architectures for the next mobile network generation, called “5G”, so as to be able to respond rapidly to extremely diverse demands in terms of traffic or quality of service.
Among the envisaged solutions, one of the most promising solutions relies on a technique known as “network slicing” in English, which is mentioned in particular in the technical report 3GPP TR 23.799 v0.2.0 of February 2016.
Such a network slicing technique allows the operator of a telecommunications network to create “bespoke” networks, capable of providing optimized solutions for very varied scenarios with very diverse constraints in terms of functionality and performance.
The concept of network slicing relies on three distinct layers, namely the “resource” layer, the “network slice instantiation” layer and the “service instantiation” layer.
The first “resource” layer comprises all the physical and logical resources of a network, in terms of calculation power, memory and transmission capability, that are necessary for the execution of the instantiation of one or more network slices.
In this respect, the so-called “physical” resources are all the equipment having calculation capabilities, storage means and transmission capabilities within a network. The so-called “logical” resources can then consist in a part of a physical resource, or on the contrary in a bundling of several physical resources that are dedicated to a network function or are shared between several network functions.
The second “network slice instantiation” layer is composed of the various instantiations of slices of the network serving to offer services, each instantiation being able to be decomposed into one or more network functions executed by physical and/or logical resources of the “resource” layer.
Finally, the third “service instantiation” layer represents services (to the user or to a company) that can be supported by the second layer, that is to say by calling upon one or more network slice instantiations to provide the network characteristics necessary for a requested service instantiation.
Thus, a network layer instantiation can be defined as being a set of network functions and of resources making it possible to execute these network functions, being akin to a complete logical network making it possible to obtain certain characteristics requested by a service instantiation.
Provision is thus made for a multitude of network slice instantiations to be able to be executed simultaneously within one and the same physical telecommunications network, so as to offer various services across this network.
However, at this juncture, user access, via the user's terminal, to one or the other of these instantiations has not been envisaged. In particular, a conventional mobile terminal in a “4G/LTE” network is always connected to a single very specific MME entity (“Mobility Management Entity”) and a single very specific gateway S-GW which in this instance are situated in the core of the mobile telecommunications network, in order to be able to obtain various services and to access external networks.
A conventional mobile terminal does not therefore have the ability to be able to connect to various instantiations of network slices such as may be envisaged in future networks, which rely potentially on diverse and varied physical and logical resources.